Electrical timing system



June 6, 1944. L?. w. MELCHER ELCTRICAL TIMING SYSTEM Original Filed June2l, 1940 4 Sheets-Sheet 1 /VVENT/ .ZEE I/K/VELCHER,

By M A L..'w. MELcHER f 2,350,409 ELECTRICAL TIMING SYSTEM June 6, 1944.

Original Filed Jne 21, 1940 4 Shee-ts-Sheet 2 .LEE WMe-L CHEAP,

- June 6, 1944. L w. MELcHl-:R

ELECTRICAL TIMING SYSTEM original med June 21, 1940 4 Sheets-ShedI 3June 6, 1944.

l L. W. MELCHER ELECTRICAL TIMING sYsTEM 4 sheets-sheet 4 Original FiledJune 2l, 1940 INVENTO? .LEE W/Vfz CHER,

, /QWURNEV Patented June 6, 1944 ELECTRICAL TIMING SYSTEM Lee W.Melchor,

Waukesha. Motor Comp corporation of Wisconsin Original application June21, 1940, Serial No.

341,747. Divided and this ap conomowoc, Wis., assignor to any, Waukesha,Wis., a

plication September5, 1942, Serial No. 457,507

(Cl. V75-375) 6 Claims.

This invention relates to electrical timing systems and moreparticularly to relay apparatus and associated circuits for operatingelectrical circuit making and breaking devices upon the expiration ofpredetermined time intervals. This application is a division ofapplication Serial No. 341,747, filed June 2l, 1940, now Patent No.2,307,845 dated January l2, 194,3.

An object of this invention is to provide an improved electrical timingsystem comprising a plurality of relay devices adapted to provide timedelectrical impulses for operating an impulse circuit making and breakingdevice.

Another object of this invention is to provide an improved electricaltiming system having a minimum number of operational elements which ispositive and automatic in operation.

Another object of this invention is toprovlde an improved electricaltiming system comprising timing relay elements interconnected in acircuit which operates in accordance with the manner of energizing saidcircuit.

A further object is the provision of a novel electrical timing systemwhich is simple and inexpensive in construction, has flexible operatingcharacteristics and is durable in use.

These and other objects and advantages of the invention will be apparentfrom the following description, the appended claims and the accompanyingdrawings in which like reference characters designate like parts in theseveral views, and in which:

Fig. 1 is a wiring diagram of the electrical timing system arranged inaccordance with the present invention embodied in a circuit forcontrolling an engine-generator unit;

Fig. 2 is a simplified across-the-line diagram of the system shown inFig. 1;

Fig. 3 is an elevational view, partly broken away, of a portion of thetimer mechanism;

Fig. 4 is a bottom plan view of the mechanism shown in Fig. 3 with thecover member for the mechanism indicated thereon;

Fig. 5 is a perspective detail of the plunger of the mechanism of Fig.3; and

Fig. 6 is a perspective detail oi the pawls in the mechanism of Fig. 3.

The drawings illustrate a preferred embodiment of the invention and inFigs. l and 2 disclose the electrical timing system embodied as a partof a control system for an engine-generator unit at a period duringacycle of operation when the engine and generator are both inoperativeand the system is under the control of the electrical timing systemwhich operates from the battery of the system and predetermines a timelimit after which the engine-generator will become auf tomaticallyoperative to recharge the system-battery, if required, and to supply acurrent to rany load connected to the battery at the time. The

. switch operates one, two, three or more sets of generator isdesignated by the reference numeral I0 and, as shown'in Fig. l, ismechanically coupled to an internal combustion engine II by a driveshaft I2. A storage battery I3 or the like normally supplies a source ofE. M. F. for any desired load through the leads I4 and I5 and is adaptedto be periodically recharged by the engine-generator. The battery I3 andthe enginegenerator IIJ-I I, for example, could provide for supplying alighting, heating, Ventilating or other load for domestic, farm orindustrial purposes or for a bus, trolley bus, railway car or the like.

To simplify the description of the electrical timing system of thecontrol system for the engine-generator I0-II the various relays andswitches of the system will be designated by reference letters and thecontacts operated thereby will be designated by the same referenceletters With the numerals 1, 2, 3, etc., appended thereto depending uponwhether the relay or contacts. To facilitate further an understanding ofthe invention the description of the preferred embodiment will beseparated into the several phases of operation thereof.

THE MAIN POWER CIRCUIT A. Upon operation of the generator as a motorReferring to the drawings and more particularly to Fig. 2, one side ofthe generator I0 is connected to the negative side of the battery I3 bythe lead 20. From the other side of the generator the circuit iscompleted through a series starting eld SF, a starting resistor SR., anormally open starting contactor SCI, a starting fuse 2I, and thenceback to the positive side of the battery through leads 22 and I4. Uponclosing of the starting contactor SCI the battery I3 will thus operatethe generator I0 as a motor to efrect cranking and starting of theengine I I.-

B. Upon operation of' the generator as a generator The negative side ofthe generator is again connected to the negative side of the battery bythe LI of a low current relay, a series coil GRSC of a generatorregulator GR, a generator fuse 21, a series coil RISC of a reversecurrent relay RI, a contact RII of the reverse current relay, thearmature 28 of the reverse current relay, and thence through the leads29, 22 and I4 to the positive side of the battery I3. Excitation for thegenerator I0 is obtained from a shunt iield ShF which is connected tothe negative side of the generator by a lead 30 connecting with the lead20. The other side of the shunt iield ShF is connected to the positiveside of the generator by a lead 3I which connects to the main generatorcirgine II and closing of the contacts RII of the reverse current relaythe generator Will operate to supply a current to the battery I3 and theload leads I4 and I5.

THE ELECTRICAL TIMING SYSTEM Assuming the battery I3 to be at leastpartly charged and the control circuit to be in the condition indicated-by Figs. 1 and 2., the electrical timing system will be under operationof the'battery as stated above to predetermine the next operation of theengine-generator. The timing System comprisesa relay FTR, a 'relay STRand an impulse timing device including a timer solenoid TS and issupplied with energy in a manner dependent upon the condition of theengine-'generator control system. Both theV relays FTR and STR are ofthe quick make, slow break type, but the relay FTRV has its contactsFTRI normally closed when the relay is deenergized while the contactsSTRI of relay STR are normally open upon deenergization of the relay.Thus the contacts FTRI Will open only after a predetermined timefollowing energization of relay FTR while the contacts STRI reopen aftera predetermined time following deenergization of relay STR.v The relaysFTR and STR may bel of any conventional design andare so adjusted in thepreferred embodiment of the invention that the normally closedY i relayF'I'R opens its contacts FTRI approximately 5 seconds afterlenergization thereof while the normally open'relay VSTR reopens itscontacts STRI only after approximatelyA 3 minutes followlowingdeenergization thereof; The time delay in the opening ofnormally-.closed contacts FTRI upon energization of relay FTR and thetime delay in reopening of the normally open contacts S'IRI upon thedeenergization of relay STR Vmay be obtained by employing friction,pneumatic, hydraulic or magnetically actuated means. The use of adash-pot mechanism which serves to retard the movement of the armatureof relay FTR has beeny found convenient for obtaining the olesired delayin the opening ofcontacts FTRI upon thel energizationA of relay FTR.Similarly, the movement of the larmature which controls the contactsSTR! Imay be retarded upon the deenergization of relay STR either by useof a dashpot mechanism acting against gravity on said armature or thetension of a biasing spring or else by the use of a field corearrangement which retards the dying-out of ux in the magnetic circuit ofthe relay. Dash-pot controlled and decadent flux relays per se are knownin the art and the structure thereof forms no part of the presentinvention.

Referring again to Fig. 2 in particular, the control circuit for relayFTR comprises a lead 35 which connects with the negative lead I5 of thebattery I3, a lead 36, the coil FTR of the relay,

a lead 37, the contacts STRI of the relay STR, the lead 38 and a leadY39. whichconnectsthrough a.. control circuit fuse All, the startingfuse 2I, the leadr22 and the lead I4 to the positive side rof thebattery. The leads 35 and 3S are thus nor- Y is attached to the base 53.

mally connected across opposite sides of the battery I3 and acrossopposite sides of the generator IG upon operation of the generator,andas best shown in Fig. '2, supply the voltage of the Y a lead 45 (Fig.2) which connects with the lead 39 and thence to the positive side ofthe battery I3, and on the other side the normally closed contacts FTRIof the relay FTR and the lead 46 which I connects atthe point 41 to thestarting circuit of the generator between the starting eld SF and thestarting resistor SR.

From the above description it will be evident that when the generator I0is at a stand-still a circuit is established betweenthe batteryI3, lead20, generator Ill, series `eld SF, point 41, lead 46,

the normally closed contactsFTRI, the coils of fthe relay STR andsolenoid TS,`the lead 45 and the lead 39back to the other side of thebattery.

Y This causes Aenergization of the relay STR and rapid closing of thecontactsSTRI thereof. Upon closing of the contacts STRI,` the relay FIRis energized across the lines and 33 and after approximately 5 secondsopens its contacts FTRI.

Upon opening of the contacts FTRi the coil of relay ISTR Aand of thesolenoid TS become deenergized and after approximately 3 minutes Vthecontacts STR! of relay STR open to deenergize the coil of relay FTR. Thecontacts FTRI then rapidly close and again energize the relay STR andthe solenoid TS. The cycle of operation is thus repeated as long as boththe relays FTB.A v and S'IR are subjected to battery potential, andV'since thev solenoid vcoil TS is connected in parallel with the relaySTR, the solenoid receives an energizing impulse at approximately 3minute'intervalsf Upon starting of the engine-generator, however, vandthe generation of a potential in the generator I0, the polarity of thepoint 4l' changes from that of the negative side of the battery I3 tothat; of the positive side ofthe generator. Since i the startingcontacter SCI opens upon operation of the engine-generator, as will behereinafter described, 'and as the resistance of the series coils LI,IGRSC and RISC of the main power circuit is practically negligible, thepotential across the relay STR is insuicient to effect furtherenergizetion thereof and the operation of the timer thus automaticallyterminates upon operation of the engine-generator.v Upon termination ofthe operation of the engine-generator, however, therelay STR is againsubjected to substantially battery potential and the timer automaticallyre- -sumes operation.

As described above, the solenoid TS receives an impulse each time thatthe relay STR is energized and thus at approximately 3 minute intervalsduring the operation of the timer. The impulse timing device forms thesubject-matter of application Serial No. 376,566, le'd January 30, 1941,which is a divisional application of Serial No. 341,747, filed June 21,1940. As is shown in Figs. 3 to 6, the solenoid TS of the impulse timingdevice operates a plunger 56 which in turn l Voperates a pawl 5Iassociated with a ratchet wheel 52. The solenoid TS is rigidly mountedin preldetermined positioning on a base member 53 by means of a clampingbracket 54 which extends around the outer surface of the solenoid coiland To provide for removably receiving the solenoid the clamping'bracket 54 is split as indicated at '56 and clamping screws 51 providefor releasably clamping the bracket around the solenoid. To furtherassure that the solenoid will remain in fixed position on the base 53during operation of the device, the clamping bracket 54 is also providedwith an inturned flange 58 which extends around the upper end of thesolenoid when in place in the bracket.

The plunger 50 is of generally circular crosssection and is providedwith an upper portion 60 which is received within the interior of thesolenoid coil TS and provides the movable core ofI the solenoid. Thisportion 60 is relatively ciosely received within the bore of thesolenoid coil and thus provides a support and guide for the upperportion of the plunger 50. The connections to the solenoid are such thatupon energization thereof the plunger 50 is pulled upwardly. This upwardmovement of the plunger in response to energization of the solenoid islimited by a'portion 6| of the plunger that is of increased diameter andprovides a shoulder which engages the lower end of the solenoid coil andprevents further upward movement of the plunger. Downward movement ofthe plunger 50 upon deenergization of the solenoid is positively assuredby a spring '62 which surrounds the plunger and is compressed betweenthe bottom of the solenoid and a collar 53 provided on the plunger belowthe portion 6|.

The plunger 50 at its lower end is provided with an extension $4 whichis of substantially rectangular cross-section as shown in Figs. 4 and 5and which is slidably received within. a correspondingly shaped groove65 of an upstanding boss `|56 provided on the base 53. The portion 64 ofthe plunger is normally maintained in the groove 65 by a cap member -61which is screwed to the boss 6B. The boss 66 and the cap vS1 incooperation with the extension 5310i the plunger thus provide a supportand guide for the lower end of the plunger 50 and also prevent turningof the plunger about its longitudinal axis during operation of thedevice. Downward movement of the plunger under action of spring 62 islimited by a flattened portion '68 of the plunger which provides ashoulder 69 that engages the upper side of the boss SB and cap 61. Thearrangement of the various parts thus far described is such that uponeach successive energizing impulse of the solenoid TS the pawl willrotate the ratchet wheel 52 through an angle corresponding to the pitchof one of the teeth of the ratchet wheel.

The pawl 5| is pivotally mounted on the portion 68 of the plunger 50 asindicated at 12 and is provided with a nose piece 13 that is adapted toengage and operate the teeth of the ratchet wheel 52. To provide formaintaining the nose piece 13 of the pawl in positive engagement withthe teeth of the ratchet wheel and thus assure a step-by-step rotationof the ratchet wheel upon each energization of the solenoid TS, the pawl5| is also provided with an extension 13 to which one end of a tensionspring 15 is attached. The

other end of the springr 15 is attached to a screw` 16 or the like whichthreads into the plunger 50 and thus maintains the nose piece 13 of thepawl in constant engagement with the teeth of the ratchet wheel whilepermitting retraction of the pawl upon deenergization of the solenoidand dropping of the plunger. To provide for ready retraction of the pawl5| upon deenergiz-ation of the solenoid the plunger 50 is provided witha notched or cutaway portion 11 permitting free movement of the pawl.The construction and plunger will be readily apparent from Figs. 3, 5and 6.

To prevent reverse movement of the ratchet wheel 52 and thus to furtherassure a one step advance of the ratchet wheel upon each energization ofthe solenoid TS a second pawl similar in construction to the pawl 5| isprovided and is so arranged that its nose piece 8| engages the teeth ofthe ratchet wheel in such manner as to permit operation of the ratchetwheel under operation of the solenoid TS while preventing backwardmovement of the ratchet wheel. The pawl 80 is pivotally mounted on aboss 82 provided in the base 53 as indicated at 83 and is also providedwith an extension 84 to which one side of a tension spring 85 isattached. The other side of the spring 85 connects with a stud 80 or thelike provided on a boss 81 mounted on the base 53, and thus the pawl 80is maintained in constant contact with the teeth of the ratchet wheel 52to prevent backward movement of the ratchet wheel while permittingforward advance thereof under action of the solenoid TS.

" The ratchet wheel 52 is rotatably mounted on the base 53 by a shaft 90and provides for operating a cam 9| which has a circular cam surface 92concentric with the axis of the ratchet wheel and one or more grooves orcam operating notches 93.Y In the illustrated embodiment the cam 9| isformed integral with the ratchet wheel 52 and is positioned on the underside of the ratchet wheel as viewed in Figs. l, 3 and 4. The shaftextends through a boss 95 providedon the base 53 vand is threadedadjacent the under side of the base to receive a nut 96 and a lock nut91. A cotter pin 98 also extends through suitable openings provided inthe lower end of the shaft 90 and positively prevents the nut 99 andlock nut 91 from working loose. The combined cam and ratchet wheel isrotatably received on the shaft 90 above the boss 95 and is preferablyprovided with upper and lower thrust bearing washers 99 and |00;respectively, which are also received on the shaft 90. A compressionspring |0| surrounds the shaft 90 above thev ratchet wheel 52 and thewasher 99 and is normally maintained in a compressed condition by acotter pin |02 which extends through a suitable opening provided in theupper end of the shaft. The cam portion 9| of the ratchet wheel is thusconstantly pressed against the washer |00 and boss and is caused to movein a predetermined path around the axis of shaft 90 'upon operation ofthe ratchet Wheel. At the same time the Cotter pin |02 and the spring|0| provide for ready removal -of the ratchet wheel and cam and theirreplacement by a wheel and cam of different operating characteristics.

As shown in Fig. 4 a cover member |03 having a glass front |04 removablyheld in place by clips |04a and screws |0l|b is adapted to be receivedon n the base 53 and encloses the timing mechanism mounted on the base.Suitable openings (not shown) are also provided in the base member forreceiving the electrical connections to the solenoid TS and the switch|05.

operation of the pawl and its mounting on the 76 The cam portion 9| ofthe ratchet wheel 52 is adapted to 'operate a switch which in thepresent embodiment of the invention controls the starting of theengine-generator Ill-H. For this purpose a switch |05 is suitablymounted on the'upper portion of the base 53 adjacent the 'solenoid coilTS and is provided with an arm |08 which carries a roller |01 thatextends into the path of movement of the cam 9| and operates upon thesurfaces 92 and 93 thereof. The switch |05 may be of any desired orstandard type `which in accordance with the present description has itscontacts maintained open so long as the roller |01 engages the circularconcentric surface 92 of the cam and closes its contacts when the rollerdrops into one of the notched grooves 93 of the cam.

From the above description it will be evident that the ratchet wheel 52and the cam 9| will bemoved through a predetermined arc of rotation uponeach energizing impulse of the solenoid TS and that the switch |05 whichis maintained in one condition of operation (open in the presentinstance) by the portion 92 of the cam will be operated to its oppositecondition upon the roller I'I falling into a groove 93 of the cam. Inthe illustrated embodiment of the invention the ratchet wheel isprovided with 40 teeth and the cam portion 9| is provided with twogrooves or notches 93 positioned diametrically apart. Thus if thesolenoid TS is energized at approximately three minute intervals asabove described, it will require approximately two hours of operation ofthe timing device to cause the ratchet wheel 52 to make one completerevolution and the switch |A will be closed Vat:approximately one hourintervals following each operation of the timer. It will be understood,however, that the timing can be readily varied by changing the number ofteeth on the ratchet wheel 52, the number and positioning of the grooves93 of the cam, or both. Thus although the number of teeth on the ratchetwheel and the timing impulses remain the same, the timing of operationof the switch |05 can be decreased to one-half hour intervals by mere-'Iy arranging four grooves 93 at 90 degrees apart and can be increasedto two hour intervals by merely arranging one groove 93 on the surface92 of the cam. In like manner any other desired timing arrangement canbe obtained by properly regulating the number of teeth on the ratchetwheel and the number and positioning of the cam grooves 93.

STARTING or THE ENGINE-GENERATOR In accordance with the presentinvention, as described above, the impulse timing device switch IIJ-5 ofthe electrical timing system controls the starting of theengine-generator I 0-I I. Referring to Figs. 1 and 2, and moreparticularly to Fig. 2, the control circuit for eiecting starting of theengine-generator comprises the lead 39, a lead |I0, the coil of acontrol circuit relay CCR, leads III and II2, the contacts of theimpulse timing device switch |05, and thence through leads II3, |I4 and35 to the other side of the battery I3. Also included in the controlcircuit thus described is a starting contactor coil SC which isconnected in parallel with the rent relay are normally closed asillustrated when the generator I0 is idle or is operating as a motor tocrank the engine II. Thus when the normally open contacts of theautomatic timer switch |05 are closed by operation of the timer,

both the control circuit relay CCR and the starting contactar SC will bebattery I3.

Upon energization of the starting contacter SC the normally openstarting contact SCI operated thereby is caused to close and thuseffects energization of the generator I 0 as a motor through the seriesstarting field SF to provide for cranking the engine II. At the sametime the energization of the control circuit relay CCR causes theopening of the contacts CCRI thereof which are normally closed tocomplete a shorting-circuit from an engine magneto |20 to a ground I2Iby way of leads |22 and |23. The magneto I 20 is thus conditioned uponopening of the contacts CCRI to supply an ignition current to the engine`II and eiect the starting thereof under the cranking operation of thegenerator I0 running as a motor. Under normal conditions of operationthe internal combustion engine II will thus start and will then drivethe generator I0 as a generator.

OPEaATroN or THE CONTROL SYSTEM UPON START- me or THE ENGINE-GENERATORenergized across the Assuming starting vof the engine II as abovedescribed, it will be evident that in order to continue operation of theengine the control circuit relay CCR must remain energized to preventclosing of the contacts CCRI and grounding of the magneto. This isaccomplished by a set of contacts CCR2 which are normally open` andwhichV are closed upon energization of the relay coil CCR to establish ashunt holding circuit by way of the leads |25 and |25 around thecontacts of the timer switch |05. Thus the engine |I l will continue tooperate although the impulse timing switch may be opened by theelectrical timing system. I

Upon starting of the engine I I and driving of the generator I0 as suchthe generated voltage will build up and upon this voltage reaching apredetermined Value, one half to one volt above the voltage of thebattery I3 for example, the reverse current relay RI operates and causesthe back contact RI2 thereof to open and the main contact RII and theback contact RI3 to close. Upon opening of the contact RIZ theenergizing circuit for the starting contactar SC is opened and thecontacter SCI Vis caused to open the starting circuit of the generatorI0. Upon closing of the main contacts RII of the reverse current relay,however, the main generator circuit is closed and the generator I0 isconnected to the leads I4 and I5 to supplyv a recharging current to thebattery I3 and to provide a source of voltage to any load connected withthese leads.

As described above, the back contact R13 of the reverse current relaycloses when the contact R12 thereof opens. This contact R13 controls theenergization of a potential coil GRPC of the generator regulator GR.Again referring to Fig. 2. the circuit for this potential coil GRPC ofthe generator regulator comprises the negative side of the generator I0,the leads 20, I5. 35 and H4, relay contacts CCR2, leads III and IIE, thecontacts R13 of the reverse current relay, a lead ISI, the potentialcoil GRPC, a temperature compensating resistor I 32, and a lead |33which connects with the positive side of the generator at the point 32of the main generator circuit. Thus upon operation of the generator andclosing of the contact R13 the coil GRPC will be energized by thepotential of the generator I9.

To permit ready starting of the engine I I, however, and to permit theengine-generator to come up to speed before a full load is appliedthereon an unloading resistor ULR is connected in a closed circuit withthe resistor |32 for a predetermined period of time and provides forlimiting the generated voltage to a sub-normal value during this periodof time. The circuit for the unloading resistor ULR is controlled by thecontrol circuit relay CCR and by the automatic timer relay STR of theelectrical timing system which also predetermines the time that theunloading resistor will be connected in the control circuit of thegenerator. This circuit comprises a lead |36 which connects to a point|31 intermediate the coil GRPC and one side of the resistor |32, thenormally open contacts CCR3 of the control circuit relay CCR, lead |31a,the unloading resistor ULR, leads |38 and 31, the contacts STRI of relaySTR, and thence through leads 38, 39, 22 and 29, contact RII which isclosed when the generator is operating, coil RISC, fuse 21 and the point32 which connects with the lead |33 that connects with the other side ofthe resistor |32. During the starting of the engine II, both the controlcircuit relay CCR and the timer relay STR are energized to close theirnormally open contacts CCR3 and STRI, respectively, and thus the circuitis completed for connecting the unloading resistor in a closed circuitwith the resistor |32 and limiting the generator voltage. Afterapproximately three minutes time following initial cranking of theengine however, the contacts STRI of relay STR op-en to open the circuitto unloading resistor ULR and full load is applied to theenginegenerator. The normally open contacts CCR3 ofthe control circuitrelay CCR prevent a current from flowing through the resistors |32 andULR during the time that the generator Illv is idle and the impulsetiming device is operating.

Upon driving of the generator I0, furthermore, and the supplying of acurrent through its main generator connections, the coil of the lowcurrent relay LI becomes energized and effects opening of its normallyclosed contacts LII.

OPERATION F CONTROL SYSTEM UPON FAILURE 0F ENGINE To START As describedabove, the engine II normally starts to drive the generator I3 uponclosing of 1 limit switch CLS which automatically stops the.v crankingoperation if the engine fails to start within a predetermined period oftime and which must be manually reset in order to effect furtheryoperation of the system.

The intermittent switch IS is of the thermally responsiveself-energizing and deenergizing type and comprises a normally closedset of contacts ISI which are connected in the lead I I I above thecontrol circuit relay coil CCR (see Fig. 2) and a heater element ISCwhich is also connected to the lead between the contacts ISI and thecoil CCR by the lead |43. The circuit for the heater element ISC iscompleted through the leads |46 and |41, the contacts LII of the lowcurrent relay LI which are normally closed as shown when the generatoris at standstill or operating as a motor, and a lead |48 which connectswith the lead 39. The thermal switch IS is so regulated in accordancewith the present invention that the contacts ISI thereof will remainclosed and effeet energization of the heating element ISC forapproximately seconds following closing of the timer switch |05 and willthen open under action of the heating element and remain open forapproximately seconds while the heating element cools. Upon opening ofthe contacts ISI the circuit for the control relay CCR and for thestarting contactor SC is interrupted even though the timer switch |65 isstill closed and thus the cranking operation of the generator Ill isstopped. Upon closing of the contacts ISI, however, iollowing cooling ofthe switch IS the cranking of the engine |I is again started and thecycle of operation thus described is repeated with each cycle ofoperation of the switch IS. Should the engine-generator start, however,the low current relay LI will be energized to open its normally closedcontact LII and the energizing circuit for the heating coil ISC is thusinterrupted to maintain its Contact ISI closed and the control circuitrelay CCR energized.

The cranking limit switch CLS prevents this cyclic operation of thecontrol circuit from operating indefinitely if the engine II stillcontinues not to start. The switch CLS is also of the thermallyresponsive type and comprises a heating element CLSC and normally closedcontacts CLSI. The heating element CLSC of the switch CLS is connectedin parallel with the intermittent switch IS and thus upon closing of theimpulsertiming device switch |05 a circuit is cornpleted through theelement CLSC by way of lead III, a lead which connects with the lead Iat a point |5I above the contacts ISI of the intermittent switch IS, theheater element CISC, leads |46 and |41, the normally closed contacts LIIof the low current relay, and the lead |48 which connects with the lead39. The contacts CLSI of the cranking limit switch are connected in thecontrol circuit lead 39 ahead of any of the circuits for the controlcircuit and thus entirely disconnect the control circuit when the heaterCISC operates to open the contacts CLSI. The cranking linut switch CLS,however, is set to operate at a much `slower time than the intermittentswitch IS, after approximately a three minute interval of time forexample, and thus the intermittent switch will go through several cyclesof operation during one operation of the switch CLS. Upon continuedfailure of the engine II to start, however, a-nd after the period oftime for which the switch CLS is set, it will open its contacts and willdisconnect the control circuit from the battery I3 until such time as itis manually reset as described above. It will be evident, however, thatif the engine-generator starts within the time for which the switch CLSis set, the energizing circuit for the heating element CLSC will bebroken by opening ofthe contacts LII of the low current relay and thecontacts CLSI will remain closed to maintain the control systemenergized.

TERMINATION or OPERATION or 'rr'rE ENGINE- GENERATOR minimum the lowcurrent relay LI will become deenergized and operate to close itscontacts LII.

The heater ISC of the intermittent switch IS will thus be againenergized across the llines 35 and @9 and after approximately 15 secondswill open its contacts ISI. The opening of the contacts ISI causes thecontrol circuit relay CCR to become deenergized and the consequentoperation of its several sets of contacts. Thus the magneto circuitcontacts CCRI are closed while the holding-circuit contacts CCR2 and thecontacts CCR3 of the unloading resistor circuit are opened. Upon closingof the contacts CCRI, the magneto |20 of engine I-I is grounded throughground I2I and the engine terminates its operation. The thermal switchIS, however, prevents stopping of the engine II because of somemomentary decrease in the current of the generator IU.

When the generator I ceases to operate there will be a tendency forcurrent to flow from the battery I3 through the main circuit of thegenerator. The reverse current relay RI operates, however, to open themain contact RII upon even the slightest current flowing from thebattery to the generator, and thus opens the main generator circuit and,prevents any further flow of current to the generator. .At the sametime the back contacts R12 and R13 of the reverse current relay closeand open, respectively, to condition the starting contacter SC for thenext starting operation of the electrical timingsystem and to open thecircuit of the regulator potential coil GRPC.'

MANUAL CONTROL AND OPERATION oF AUXILIARY CONTROL DEVICES Although thesystem asthus far described is fully automatic in operation a means isalso provided for effecting a continuous manual control over theoperation of the system, This control comprises manually operablepush-button type of start and stop switches mounted both on the controlpanel for the engine-generator and within convenient `reach of theoperator of the system. As most clearly shown in Fig. 2a normally closedstop switch |55, which may be a panel switch, is connected in the lead|I4 of the circuit for the control circuit relay CCR and may be openedat any time to open this circuit and stop the engine II by closing the.grounding Circuit |20-I2I 0f the engine magneto |20.. ln like manner anormally closed stop switch |56, which may be under constant control ofthe operator, is interposed in the lead III aboveV the point I5I (seeFig. 2) and provides for stopping the engine-generator at any time.Connected across the leads |I2 and Ils in parallel with the contacts ofthe automatic timer switch |05 and the holding contacts CCR2 of thecontrol circuit relay CCR are two normally open manual starting switches|51 and |58, one o f which may be a panel switch and the other a switchunder control of the operator, and

which when closed will ciect energization of theV control circuit relayCCR and the starting contactor SC irrespective of the condition ofswitch IBS. Thus the engine-.generator III-II can be manually started atany time, always under the control, however, of the intermittent switchIS and the cranking limiting switch CLS.

Means are also provided to automatically terminate operation of theengine-generator in the event that the engine II tips over, or in casethe oil pressure of the engine gets too low or the heat of the enginebecomes too high. Each of these latter'two means, furthermore, operatesthrough the intermittent switch IS so that a temporary disturbance inthe engine will not cause it to stop operation.

VThe means for discontinuing operation of the engine in the event thatit tips over, such for example as where the engine-generator is mountedon a bus, trolley coach, railway car or the like and the vehicle itselfturns over, comprises a tip-over switch TOS that is connected by leadsIII and |62 across the leads |22 and I 23 of the engine magnetogrounding circuit and in parallel with the contacts CCRI of thelcontrolcircuit relay. The switch TOS which is diagrammaticallyillustrated in the drawings comprises a pair of spaced contacts TOSI andTOS2 and a movable contact TOS3 adapted to engage either of the contactsTOSI and TOS2 but normally maintained by gravity or the like in an opencircuit position between the spaced contacts as shown. The switch TOS ismounted on the engine II and thus as long as the engine remainssubstantially upright the switch remains open and the magneto groundingcircuit is under control of the contacts CCRI. Should the engine tiltbeyond a predetermined degree to either side, however, such as upontipping over, the movable contact TOS3 will move into contactingengagement with one of the contacts TOSI and TOS2 and will ground themagneto I2Il through the ground I2 I, thus stopping the engine.

The means for stopping the engine II in case the oil pressure of theengine drops below a predetermined safe value comprises a pressureresponsive switch OPS which may be of any desired or standard typehaving contacts OPSI that are normally closed when the pressure is 'lessthan vthe predetermined value and are opened when the pressure is abovethis value, and which is attached to the engine to be subjected to theoil pressure therein. As best shown in Fig. 2 the contacts OPSI of theswitch OPS are connected across the leads I 4t and 39 of the controlcircuit and in parallel with the contacts LII of the low current relayby a pair of leads |65 and IEE. Thus the contacts 4OPSI of the oilVpressure switch OPS provide for completing a circuit for both the heaterelement ISC of the intermittent switch IS and the heater element CLSC ofthe cranking limit switch CLS around the contacts LII of the low currentrelay LI. Upon starting and normal operation of the engine, however, theswitch contacts OPSI oil pressure and the circuit for the heaters ISCand CLSC through these contacts will be interrupted. Should the oilpressure of the engine drop below a predetermined value, however, thecontacts OPSI will again close, or will remain closed if the pressuredoes not exceed this value upon starting of the engine, and willcomplete an energizing circuit for the heaters ISC and CLSC, althoughthe contacts LII of the 10W current relay may at the time be open. Thusunder normal operation of the system and upon failure of the oilpressure the switch IS will open its contacts ISI Vafter approximately15 seconds to eiect deenergization of the control circuit relay CCR andstopping of the Aengine II. If for any reason, however, the switch ISfails to operate, the switch CLS will operate after a further period oftime to disconnect the entire control system and thus stop the engine.It will be evident, furthermore, that although the contacts OPSIestablish a parallel circuit around the low current relay contacts LIIduring the starting of the engine-generator, both of these contacts willnor- V mally open upon starting of the engine and thus the operationofthe system is not affected. Should either of these contacts close orremain will open in response to the engine closed, however, the engineII will be stopped under control of the switches IS and CLS.

As described above, a means is also provided for terminating operationof the engine in the event that the temperature thereof rises above apredetermined safe value. This means comprises a temperature responsiveswitch ETS which may also be of any desired or standard type havingcontacts ETSI that are normally open when the temperature is below apredetermined value and are closed when the temperature rises above thisvalue and which is also attached to the engine to be subjected to thetemperature thereof. As is again best shown in Fig. 2, the contacts ETSIof the engine temperature switch ETS are connected across the leads |65and |66 oi the oil pressure switch OPS and in parallel with the contactsOPSI thereof by the leads and III. Thus if the engine temperature risesabove a predetermined value the switch contacts ETSI will close and willcomplete an energizing circuit for the switches IS and CLS to effectstopping of the engine I I` in the manner hereinabove described for thelow current relay contacts LII and the oil pressure switch contactsOPSI.

OPERATION oF 'rHE GENERATOR REGULATOR The generator regulator GR is of astandard type and is only diagrammatically shown in the drawings. Itcomprises a current coil GRSC and a potential coil GRPC which asdescribed above are Connected in series with the generator I0 and acrossthe generator, respectively, when the generator is operating to supply acurrent t0 the battery I3 or a load connected to the leads |4-I 5, andwhich provide for maintaining the current and voltage ,Withinpredetermined limits upon change in speed of the engine and change inload on the generator I0. The regulation is obtained by the carbon pileresistor CPR which controls the current flowing through the shunt eldShF of the generator. The pressure exerted on the carbon pile resistorCPR and thus the resistance thereof is Varied by suitable levers,springs, plungers and the like not shown in the diagrammaticillustration, which are operated by the coils GRSC and GRPC. If eitherthe current or the voltage tends to vary from the values for which theregulator is set, the coils GRSC and GRPC will operate to increase ordecrease the pressure on thecarbon pile resistor and thereby control thegenerator to insure reliable battery and generator protection andadequate load supply.

Thus the voltage coil GRPC of the regulator which limits the voltage ofthe generator I0 prevents overcharging of the battery |3 since thecurrent' to the battery will taper down to a low Value as the batterybecomes fully charged, while the series current coil GRSC which is setto hold the current at the rated output of the generator `preventsoverloading of the generator either by a connected load or by chargingan exhausted battery while at the same time making full output of thegenerator available when desired. To provide for varying the currentoutput of the generator, however, a plurality of shunt resistors and |16(see Fig. 1) are provided on the regulator and may be connected inparallel with the series current coil GRSC if desired. Also, asdescribed above,a temperature compensating resistor |32 vis connected inseries with the potential coil GRPC lto compensate for any changes inresist- 'ance caused by changes in the temperature thereof.

OPERATION or THE REvERsE CURRENT RELAY The reverse current relay RI isalso of a standard type and is only diagrammatically shown in thedrawings. It is of the closed magnetic circuit kind and in addition tothe series current coil RISC above described, it comprises a pair ofseries connected potential coils and |8|, a third potential coil |82, amain movable core |83, an auxiliary plunger |84, and a main andauxiliary armature 28 and |86, respectively. The current coil RISC andthe potential coil |8I operate on the main core or plunger |83 while thepotential coils |80 and |82 operate on the auxiliary plunger |84. Themain armature 28 controls the main contacts RII and the auxiliaryarmature |86 controls the back contacts R12 and R13. When the relay isin the normally open condition shown in the drawings the contacts RIIand R13 are open while the contact R12 is closed as described above.

The potential coil |82 is connected by the leads |90 and |9| across thecontacts RII of the relay so as to be energized by the diierence betweenbattery voltage and the voltage of the generator. Thus when thegenerator I0 is not operating, the coil |82 is subjected to the fullvoltage ofthe battery I3, and as the generator voltage builds up uponoperation of the enginegenerator,"the energizing voltage across the coil|82 decreases. The pull of the potential coil |82 on the auxiliaryplunger |84 provides for locking the reverse current relay in the opencondition. At the same time the current from the battery which normallyenergizes this coil also serves to partially energize the shunt eld ShFof the generator so as to assure that this iield will always build up inthe proper direction upon starting and operation of theengine-generator.

The potential coils |80 and I8| which are connected in series by thelead I 94 are connected by the leads |95 and |96 across the generator I0and are so arranged that the coil |8| which operates on the main core|83 tends to close the relay RI while the coil |80 operating on theauxiliary plunger |84 tends to replace the coil |82 and maintain therelay open as the generator voltage builds up and approaches the voltageof the battery. The potential coils |80, |8| and |82 are so designed asto maintain a proper balance vfor any battery voltage encountered in useand the gap between the main core |83 and the main armature 28 is soadjusted that the relay closes when the voltage of the generator I0exceeds the voltage of the battery I3 by a predetermined amount, onehalf to one volt for example. 'Thus upon the voltage of the generatorbuilding up to a predetermined value, the reverse current relay RIcloses to close the main contacts RII and to open the back contacts R12while also closing the back contacts R13. Since the operation of therelay depends upon the balancing action of the potential coils |80, |8|and |82, the effects of temperature changes in the coils cancel eachother and temperature compensating resistors in series with the coilsare unnecessary.

The series current coil RISC which is energized when the main contactsRII are closed provides forlocking the reverse current relay in itsclosed condition when the generator l0 is supplying a kcurrent to thebattery |3 or a connected load,

and also serves to open the relay and the contacts RII when a currenttends to flow from the battery to the generator. The current coil RISC.is thus so arrangedas to assist the action oflthe potential coil I8| onthe main core |83 to maintain the relay RI closed so long as a loadsupplying current ows from the generator and to neutralize the action ofthe coil |8| to eiect opening of the relay and the main contacts RIIupon a current flowing from the battery I3 to the generator I0. Toassure that the relay will open upon even a slight reverse currentflowing from the battery to the generator, a lead |98 is tapped into thepotential coil I 8| and is connected to a contact R14 of the reversecurrent relay which is closed upon closing of the armature 28 andcontacts RII of the relay to short out a portion ol the windings of thecoil |8I. Thus the strength of the relay closing coil IBI issubstantially decreased upon closing of the relay and the series currentcoil RISC will oper ate upon even a slight reverse current flowingtherethrough to neutralize the action of the coil I 8| and effectopening of the relay RI.

To adapt the `relay for various currents the series current coil RISC isprovided with a plurality of shunt resistors 200 and (see Fig. 1) whichmay be connected in parallel with the coil, if desired, by a lead 202and suitable contact terminals 203, 204 and 205. A pilot light PL isalso connected across the generator I0 in parallel with the seriesconnected coils |80 and I8| of the reverse current relay by the leads208 and 209 and provides for indicating to the operator when thegenerator is operating to supply a voltage to the connected load.

SUMMARY 0F OPERATION 0F THE ELECTRICAL TIMING SYSTEM relay STR and thetimer solenoid TS. The timer relay STR is thus energized and closes itsnormally open contacts STRI which completes a circuit from the batteryI3 through the relay F'Ilft.V After a predetermined time, approxi.-mately 5 seconds, in accordance with the present invention, therelatively slow opening relay FTR opens its contactsliTRI Vand thusdeenergizes both the relay STR and the timer solenoid coil TS. After alonger period of time, approximately three minutes in the presentexample, the deenergized and slower opening relay STR reopens itscontacts to deenergize the relay FIR to cause its contacts FTRI to againclose and effect energization of the relay STR and the timer solenoidTS. Thus the relays FIR. and STR will be alternately energized anddeenergized in a predetermined time cycle and the timer solenoid TS willalso be energized in a predetermined time cycle upon energization oftherelay STR.

Upon eachV energization of the timer solenoid TS, however, the ratchetwheel 52 and the cam 9| is advanced through one step of operation andthus after a predetermined number of impulses of the timer correspondingto a predetermined time period the contacts of impulse timing deviceswitch. |05 will be closed to initiate starting of the engine-generator.Upon closing of the switch contacts |05, both the control .circuit relayCCR and the starting. contactor SC will close to com dition the magneto|2i for starting of the engine II and to connect the generator I0 to thebattery for operation as a motor to effect cranking of the `engine II.If the engine Vfails to start after a predetermined cranking thereof,the self-energizing and deenergizing intermittent switch IS operates tointermittently interrupt the cranking operation. If the engine stillfails to start after a further predetermined time and predeterminedoperations of the intermittent switch IS, the cranking limit switch CLSoperates to entirely stop the operation of the engine-generator and thecontrol circuit therefor, and must be manually reset to effect furtheroperation of the system. During operation of the intermittent switch IS,however, and before operation of the cranking limit switch CLS, thecontacts of the impulse timing device switch |05 remain closed tocontinue cranking of the engine under operation of the intermittentswitch IS.

The energization of the starting contactor SC effects the closing of thestarting contactor SCI and the operation of the generator I0 as a motorto effect cranking and starting of the engine I|. Upon normal conditionsthe engine starts and upon the generator Voltage reaching one half toone volt above the voltage of the battery, the reverse current relayoperates to open the circuit to the starting contactor and to connectthe generator to its load circuit. During starting of theengine-generator, however, the unloading resistor ULR is connected inthe circuit of the generator regulator GR to limit the load on thegenerator to a sub-normal value to assist the engine-generator. incoming up to speed and is then disconnected after a predetermined timeby the contacts STR I of the timer relay STR of thel timing system.

Since the voltage of the generator I0 is limited by the generatorregulator GR the charging current of the battery I3 automaticallydecreases as the battery becomes fully charged, and when the totalconnected load current including that required to recharge the batteryI3 is less than a predetermined minimum value, the low current relay LIoperates to terminate operation of the engine-generator Ill-II. Thecontacts LIl of the low current relay LI, however, operate through theenergizing circuit of the intermittent switch IS and thus relaytermination of the operation of the engine-generator for a predeterminedtime to avoid stopping of the enginegenerator upon a temporary change inload.

As will be evident from the above description, one side of the relay STRof the electrical timing system is normally connected to one side of thebattery I3 while the other side of this relay connects toV a point 4lwhich is connected to the other side of the battery through thegenerator I0. Thus so long as the generator I0 is inoperative, the relaySTR will be energized 'across' the battery I3. Upon operation of theengine-generator, however, the polarity of the point 41 will change tothus effect deenergization of the timer 'relay STR and stopping. of thevoperation of the timing means.. `When the engine-generator terminatesoperation, however, the polarity of the point il will again. change andthus the electrical timing system will again be connected across thebattery I3v to resume operation and to predetermine the next operationof the enginegenerator.

It willv thus be apparent that upon each closing of the impulse timingdeviceswitch. |05 an energizing circuit forV starting theengine-generator Ide-I E' will be established and underV normal.conditions .of operation the engine-generator will :start and operate tosupply a recharging' current to the battery I3 and a load current to anyload connected to the leads I4 and l5. When the load current supplied bythe generator l is less than a predetermined minimum value, however, theengine-generator Will automatically stop operation. Aiter apredetermined period of time following termination of operation of theenginegenerator the impulse timing device switch will again close itscontacts iBS and the engine-generator IIJ-Il will again become operativeirrespective of the voltage of the battery or the degree of use thereof.

If during operation of the engine-generator Ill- I I, however, theengine tips over, or the engine fails to maintain a predeterminedminimum oil pressure, or the temperature oi the engine becomes too high,the operation of the enginegenerator will automatically terminate. Suchtermination of the operation of the engine-generator will be immediateupon the engine tipping over but will be delayed through operation ofthe :intermittent switch IS upon failure of the engine oil pressure orhigh engine temperature to prevent stoppage of the engine upon temporarydisturbances therein. The self-energizing and deenergizing intermittentswitch IS thus not only provides for interrupting the cranking of theengine il, but also provides for delaying termination of operation ofthe engine when the generator I'U supplies a predetermined minimum loadcurrent, or the oil pressure of the engine gets too low or the enginetemperature becomes too high.

While the form of apparatus herein described constitutes a preferredform of the invention, the invention is not limited to this precise formof apparatus and contemplates such changes and modifications as fallwithin the scope of the appended claims.

I claim:

1. An electrical timing system of the character described comprising aslow opening relay having its contacts normally closed and adapted toopen said contacts upon energization of said relay, a slow opening relayhaving its contacts normally open and adapted to reopen said contactsupon deenergization of said relay, an energizing circuit for said secondrelay including the normally closed contacts of said rst relay, anenergizing circuit for said first relay including the normally opencontacts of said second relay whereby each relay will be intermittentlyenergized and deenergized in a predetermined time cycle, and impulseoperated means adapted to be actuated upon each energization of one ofsaid relays.

2. An electrical timing system of the character described comprising aslow opening relay having its contacts normally closed and adapted toopen said contacts upon energization of said relay, a slow opening relayhaving its contacts normally open and adapted to reopen said contactsupon deenergization of said relay, an energizing circuit for said secondrelay including the normally closed contacts of said first relay, anenergizing circuit :for said first relay including the normally opencontacts of said second relay whereby each relay Willvbe intermittentlyenergized and deenergized in a predetermined time cycle, impulseoperated means adapted to be actuated upon each energization of one ofsaid relays, and switch means adapted to be operated after a,predetermined number of impulses of said impulse operated means.

3. An electrical timing system of the character described comprising asloW opening relay having its contacts normally closed and adapted toopen said contacts upon energization of said relay, a slow opening relayhaving its contacts normally open and adapted to reopen said contactsupon deenergization of said relay, an energizing circuit for said secondrelay including the normally closed contacts of said first relay, anenergizing circuit for said i'lrst relay including the normally opencontacts of said second relay whereby each relay will be intermittentlyenergized and deenergized in a predetermined time cycle, and impulseoperated means connected in parallel with one of said relays to beactuated upon each energization of said relay.

4. An electrical timing system of the character described comprising aslow opening relay having its contacts normally closed and adapted toopen said contacts upon energization of said relay, a slow opening relayhaving its contacts normally open and adapted to reopen said contactsupon deenergization of said relay, an energizing circuit for said secondrelay including the normally closed contacts of said iirst relay, anenergizing circuit for said rst relay including the normally opencontacts of said second relay whereby each relay will be intermittentlyenergized and deenergized in a predetermined time cycle, and impulseoperated means including a solenoid connected in parallel with one ofsaid relays to be actuated upon each energization oi said relay.

5. An electrical timing system of the character described comprising aslow opening relay having its contacts normally closed and adapted toopen said contacts upon energization of said relay, a sloW opening relayhaving its contacts normally open and adapted to reopen said contacts Iupon deenergization of said relay, an energizing circuit for said secondrelay including the normally closed contacts of said first relay, anenergizing circuit for said first relay including the normally opencontacts of said second relay whereby each relay will be intermittentlyenergized and deenergized in a predetermined time cycle, said rst relaybeing adjusted to open its contacts after a relatively short period oftime delay, said second relay being adjusted to reopen its contactsafter a relatively longer period of time delay, and impulse operatedmeans adapted to be actuated upon each energization of said secondrelay.

6. An electrical timing system of the character described comprising aslow opening relay having its contacts normally closed and adapted toopen said contacts upon energization oi' said relay, a slow openingrelay having its contacts normally open and adapted to reopen saidcontacts upon deenergization of said relay, an energizing circuit forsaid second relay including the normally closed contacts of said rstrelay, an energizing circuit for said first relay including the normallyopen contacts of said second relay whereby each relay will beintermittently energized and deenergized in a predetermined time cycle,and impulse timing means including a solenoid connected to be energizedupon each energization of one of said relays, a ratchet wheel operatedby said solenoid, a cam means operated by said ratchet wheel, and aswitch means operated by said cam means.

LEE W. MELCHER.

